Changes of Sagittal Spinopelvic Parameters in Normal Koreans with Age over 50.

STUDY DESIGN: A prospective comparative study. PURPOSE: To describe the changes in the spinopelvic parameters on normal Koreans more than 50 years of age. OVERVIEW OF LITERATURE: There are differing opinions regarding the changes in the thoracic kyphosis, lumbar lordosis, C7 plumb with age in the elderly population. METHODS: Sagittal standing radiographs of the whole spine including the pelvis in 132 Korean adult male volunteers more than 50 years of age were evaluated prospectively. Volunteers with a history of spine operation, spinal disease, pain in their back or legs, scoliosis, spondylolisthesis, monosegment disc space narrowing, or compression fracture in radiographs were excluded. The following parameters were included: thoracic kyphosis (T5 upper end plate [UEP]-T12 lower end plate [LEP]), thoracolumbar kyphosis (T10 UEP-L2 LEP), lumbar lordosis (T12 LEP-S1 UEP), lower lumbar lordosis (L4 UEP-S1 UEP), sacral slope, pelvic incidence, and the distances from the C7 plumb to the posterosuperior endplate of S1. These parameters in the 6th, 7th and 8th decade groups were compared and the changes in these parameters according to age were examined. RESULTS: The thoracic kyphosis demonstrated significant differences in the in the three age groups (p = 0.019), and increased with age (r = 0.239, p < 0.006). The other parameters did not show any significant difference or correlation. CONCLUSIONS: Similar global sagittal balances and spinopelvic parameters may be observed in Korean males older than 50 years, with a trend towards increasing thoracic kyphosis with age.

Role of pelvic incidence, thoracic kyphosis, and patient factors on sagittal plane correction following pedicle subtraction osteotomy.

STUDY DESIGN: An analysis of clinical and radiographic data of 40 consecutive patients with fixed sagittal imbalance. OBJECTIVE: To determine the effect of mid lumbar pedicle subtraction osteotomy (PSO), pelvic incidence (PI), thoracic kyphosis (TK), and patient characteristics on correction obtained in patients with fixed sagittal imbalance. SUMMARY OF BACKGROUND DATA: PSO is commonly performed for spinal reconstruction in patients with fixed sagittal imbalance. Prior studies have not investigated the role that osteotomy location, PI, TK, and presenting patient characteristics may play in the correction obtained after PSO. METHODS: Forty consecutive patients were identified who underwent PSO with minimum 2-year clinical and radiographic follow-up at a single institution. Data were analyzed before surgery and at 2 and 24 months after surgery to identify the magnitude and durability of correction and associated variables. RESULTS.: C7 plumb line improved from mean 15 cm anterior to the sacrum before surgery to 3.0 cm after surgery and 4.5 cm at 24 months (P < 0.0001); mean PSO wedge size was 32.4 degrees . Patients treated for idiopathic deformity (typically following prior Harrington rod fusions) had better maintenance of correction than patients with degenerative sagittal imbalance, although not statistically significant (P = 0.06). Fusion to the upper thoracic spine preserved correction better than fusion to the thoracolumbar junction. Sagittal plane correction, SRS outcome scores and Oswestry scores were equivalent comparing PSO's performed at L2 and L3.Using our patient data, we tested models of PI and TK to predict the lumbar lordosis needed to achieve ideal sagittal balance. The formula PI + LL + TK < or =45 degrees showed 91% sensitivity for predicting ideal sagittal balance at 24 months (P = 0.001). CONCLUSION: PI and TK can predict the lumbar lordosis necessary to correct sagittal imbalance in patients under-going PSO with high sensitivity. Sagittal correction and clinical outcome scores were equivalent comparing PSO's performed at L2 and L3. Patients with degenerative sagittal imbalance and those with shorter fusions are more likely to lose correction with time.

Neurologic complications of lumbar pedicle subtraction osteotomy: a 10-year assessment.

STUDY DESIGN: Clinical, radiographic, and outcomes assessment focusing on neurologic complications in patients undergoing pedicle subtraction osteotomy (PSO). Clinical data were collected prospectively. Radiographic analysis was performed retrospectively. OBJECTIVE: To evaluate intraoperative and postoperative neurologic deficits following lumbar PSOs in order to determine risk factors, treatment strategies, and patient outcome. SUMMARY OF BACKGROUND DATA: Although technically demanding, PSOs have been increasingly used to restore lumbar lordosis and correct sagittal deformity. Although some reports have commented on various complications of the procedure, to our knowledge, there have been no studies focusing on neurologic complications of the osteotomy. METHODS: An analysis of 108 consecutive patients with an average age of 54.8 +/- 14.0 years and treated with a lumbar PSO at 1 institution over a 10-year period (1995-2005) was performed. Medical records, radiographs, and neuromonitoring data were analyzed. Clinical outcome was assessed using the Oswestry Disability Index and the Scoliosis Research Society (SRS)-24 instruments. RESULTS: A total of 108 PSOs were performed. Following surgery, lumbar lordosis increased from -17.1 degrees +/- 19.3 degrees to -49.3 degrees +/- 14.7 degrees (P < 0.000), and sagittal balance improved from 131 +/- 73 mm to 23 +/- 48 mm (P < 0.000). Intraoperative and postoperative deficits (defined as motor loss of 2 grades or more or loss of bowel/bladder control) were seen in 12 patients (11.1%) and were permanent in 3 patients (2.8%). With time motor function improved by 1 grade in 2 patients and all 3 were able to ambulate. Intraoperative neuromonitoring did not detect the deficits. In 9 patients, additional surgical intervention consisted of central enlargement and further decompression. Deficits were thought to be due to a combination of subluxation, residual dorsal impingement, and dural buckling. CONCLUSION: Intraoperative or postoperative neurologic deficits are relatively common following a PSO; however, in a majority of cases, deficits are not likely to be permanent.